00743245

Component

https://doi.org/10.3141/1586-03

http://scholar.google.com...rner&publication_year=1997

An effort is made to summarize current practices for modifying paving asphalts. The types and classes of modifiers used, or considered, for paving applications are reviewed. The applicability of the Superpave binder specification (AASHTO MP1) is reviewed critically, and the modified-asphalt characteristics that are not considered in this specification are evaluated. Conventional testing results of modified binders are compared with Superpave testing results. The results indicate that a variety of additives can be classified, on the basis of their composition and their effects on asphalts, as polymers (elastomeric and plastomeric), fillers, fibers, hydrocarbons, antistripping agents, oxidants, antioxidants, crumb rubber, and extenders. These additives vary significantly in their physical and chemical characteristics and are expected to have widely variable effects on performance-related properties of asphalts. The assumptions supporting the criteria in the Superpave binder specification may not be valid for some modified binder systems. Furthermore, the testing protocols included in the specification do not consider certain important characteristics that are typical of particular modified binders. Among these characteristics are strain dependency, thixotropy, loading-rate dependency, and time-temperature equivalency. Conventional measurements used currently by state departments of transportation such as ductility, elastic recovery, and resilience, were collected. The ranking of five modified systems on the basis of conventional and Superpave measurements was analyzed. The analysis does not indicate that the conventional test methods are consistent in their rankings, nor does it indicate that these measures add much to the information deduced from the Superpave data.

This paper appears in Transportation Research Record No. 1586, Asphalt Binders and Binder Specifications.

English

p. 16-23

1997

Transportation Research Record

030906208X

Figures (8) ; References (12) ; Tables (2)

Antioxidants; Antistrip additives; Asphalt; Crumb rubber; Ductility; Elasticity (Mechanics); Extenders; Fibers; Fillers (Materials); Hydrocarbons; Loads; Oxidizing agents; Polymers; Resilience (Materials); Specifications; Superpave; Thixotropy

Loading rate; Modifiers; Recovery (Mechanics)

Highways; Materials; I31: Bituminous Binders and Materials

TRIS, TRB, ATRI

Dec 3 1997 12:00AM

• CHARACTERIZING ASPHALT VOLATILITY
• DEVELOPMENT OF SUPERPAVE DIRECT TENSION TEST DEVICE
• NEW, SIMPLE, RAPID, AND PRECISE METHOD FOR TRACE ANALYSIS OF NICKEL AND VANADIUM IN PETROLEUM ASPHALT
• PRODUCTION OF ASPHALT-RUBBER BINDERS BY HIGH-CURE CONDITIONS
• QUANTITATIVE ANALYSIS OF POLYMERS AND CRUMB RUBBER IN HOT-MIX ASPHALTS
• STUDY OF STRATEGIC HIGHWAY RESEARCH PROGRAM PRESSURE AGING VESSEL PROCEDURE USING LONG-TERM, LOW-TEMPERATURE AGING EXPERIMENTS AND ASPHALT KINETICS
• USE OF VISCOSITY STANDARD FLUID TO CONTROL QUALITY OF RHEOLOGICAL MEASUREMENTS FOR CHARACTERIZING ASPHALT BINDERS